Radiocapsule for registering ionizing radiation in the cavities of human bodies

ABSTRACT

A radiocapsule for registration of ionizing radiation in the cavities of human body, comprising a detector to register ionizing particles in the cavities of human body and to modulate r.f. signals of an inverter of a d.c. voltage into an a.c. sine voltage at the moment when ionizing particles are being registered, said inverter having a piezo-electric transformer.

United States Patent Pluzhnikov et al.

[451 Sept. 12, 1972 [54] RADIOCAPSULE FOR REGISTERING IONIZING RADIATIONIN THE CAVITIES OF HUMAN BODIES Inventors: Viktor MikhailovichPluzhnikov,

Filed:

Studenchesy gorodok MIFI, Korpus 6, kv. 32; Karl Davidovieh Kalantarov,ulitsa Serafimovicha, 2, kv. 469; Jury Yakovlevich Gugnin,Timiryazevskaya ulitsa, 10/12, kv. 108; Valentin Sergeevich Semenov,ulitsa Garibaldi, 23/56, Korpus 1, kv. 79; Valentina VasilievnaZelenina, Studenchesky gorodok MIFI, Korpus 9, kv. 15; Albert IvanovichFilatov, Nagomaya ulitsa, 64, 2a, kv. 61, all of Moscow, USSR.

Aug. 5, 1970 Appl. No.: 61,370

US. Cl ..128/2 A, 128/2 P, 128/2.1 A,

Int. Cl. ..A61b 5/07 Field of Search ..128/2 A, 2 P, 2.1 A, 2.1 R;

References Cited UNITED STATES PATENTS 4/1971 Temps et a1. ..128/2.1 A

Ros en ..321/8 2,975,354 3/1961 3,453,546 7/1969 Fryer ..128/2.1 A3,478,344 11/1969 Schwitzgebel et a1. .128/2.1 A 3,427,454 2/ 1969 Webb..128/2.1 R 3,487,239 12/1969 Schafft ..310/8.5 3,562,792 2/ 1971Berlincourt et a1 ..310/8 3,562,563 2/1971 Schafft ..310/9.5 3,518,5736/1970 Smith ..331/163 X FOREIGN PATENTS OR APPLICATIONS 244,402 4/1963Australia ..l28/2 P OTHER PUBLICATIONS Intern. Conference MedicalElectronics, 1959, pp. 300-306 Primary Examiner-Kyle L. HowellAtt0rneyWaters, Roditi, Schwartz & Nissen [57] ABSTRACT A radiocapsulefor registration of ionizing radiation in the cavities of human body,comprising a detector to register ionizing particles in the cavities ofhuman body and to modulate r.f. signals of an inverter of a d.c. voltageinto an a.c. sine voltage at the moment when ionizing particles arebeing registered, said inverter having a piezo-electric transformer.

1 Claim, 1 Drawing Figure PATENTEDSEP 12 I972 'llllll I RADIOCAPSULE FORREGISTERING IONIZING RADIATION IN THE CAVITIES OF HUMAN BODIES Thepresent invention relates generally to radiotelemetric systems forexamination of the cavities of human body and more specifically, toradiocapsules for registration of ionizing radiation in the cavities ofhuman body, with the radiocapsules serving as transmitters inradiotelemetric systems.

There exist in the art nowadays radiocapsules for registration ofionizing radiation in the cavities of human body, comprising a detectorwhich registers ionizing particles in the cavities of human body andmodulates r.f. signals generated by an oscillator at the moment theionizing particles are being registered.

In the aforementioned radiocapsules an r.f. oscillator is formed as al.f. relaxation inverter of a d.c. voltage into an a.c. pulsing voltage,and with the inverter incorporating a multicircuit transformer. At themoment the ionizing particles are being registered, the detector causesthe relaxation frequency of the inverter to vary, thereby providingfrequency-pulse modulation of the r.f. signals being emitted.

Provision of a multicircuit transformer possessing a large number ofturns in the prior-art radiocapsules adversely affects theirreliability, renders them too complicated to make and inadequately smallin size.

Furthermore, provision of the r.f. oscillator as a relaxation inverterfeaturing pulse frequency modulation, is responsible for the dissipatedpower of r.f. signals which, in turn, affects in a detrimental mannerthe jamming invulnerability of the radio emission, impedes the obtainingof the required time resolution of the ionizing emission registrationand complicates the entire construction of a radiotelemetric system.

It is an object of the present invention to provide a radiocapsule forregistering ionizing radiation in the cavities of human body that willensure an increased reliability and a higher quality of the registrationof ionizing radiation.

It is another object of the present invention to provide a radiocapsulefor registering ionizing radiation in the cavities of human body whichhas a small size and an improved production technology therefore.

According to the above-stated objects in a radiocapsule for registrationof ionizing radiation in the cavities of human body, comprising adetector which is to register ionizing particles in the cavities ofhuman body and to modulate r.f. signals generated by an oscillator atthe moment the ionizing particles are being registered,, the r.f.oscillator in accordance with the invention is made as an inverter of ad.c. voltage into an a.c. sine voltage and comprises a piezo-electrictransformer electrically connected to the detector so as to ensure anamplitude modulation of the r.f. signals generated.

Such a construction of the herein-disclosed radiocapsule renders it morereliable, improved its production technology, reduces its size andsimplifies the construction of a radiotelemetric system as a whole.

The nature of the present invention is explained in the followingdisclosure of an exemplary embodiment thereof in conjunction with theaccompanying drawing, wherein a circuit schematic of the herein-proposedradiocapsule is represented.

Referring now to the drawing, the radiocapsule for registration ofionizing radiation in the cavities of human body, according to theinvention comprises a detector which is adapted to register ionizingparticles in the cavities of human body (not shown in the drawing), saiddetector including a Geigen Muller counter 1 which modulates the r.f.signals generated by an oscillator 2 at the moment when ionizingparticles are being registered, as well as comprising a rectifier 3 anda d.c.

low-voltage source 4 to supply power to the oscillator 2 The r.f.oscillator 2 is made as an r.f. inverter for a 5 which is prepared frompolarized piezoceramics and having three electrodes (common, input andoutput ones) applied to the plate surface as a thin silver coatmg.

The rectifier 3 is built around diodes 10 and 11 and a capacitor 12according to the voltage-doubling circuit.

The principle underlying the operation of the proposed radiocapsuleresides in the variation of the resistance of the G-M counter 1 inresponse to the process of registering the ionizing particles.

To register ionizing radiation in the cavity of a human body underexamination the radiocapsule is to be introduced directly into thecavity to be examined.

The initial resistance of the G-M counter l is not to exceed 10 ohms,whereas a discharge caused by ionizing particles results in theresistance dropping down to IO IO ohms.

Voltage necessary for the operation of the G-M counter 1 is fed theretothrough the rectifier 3 from the output electrode of the piezo-electrictransformer 9. A positive feedback voltage required for the inverteroperation is fed from the same electrode through the capacitor 6 to thebase of the transistor 5. Thus, the G- M counter 1 is therebyelectrically connected to the inverter positive feedback circuit.

The resonance and degree of polarization of the transformer 9, as wellas the value of the inductance 7 are so selected that the inverteroperates under nominal (full-load) conditions only if the resistance ofthe G-M counter 1 loading the inverter reaches its maximum value, i.e.,at zero discharge in the counter. As a result the inverter emits r.f.waves at a constant (maximum) amplitude and at an oscillator generationfrequency which lies within the broadcast frequency bandwidth. Theprincipal emitting element is the inductance 7. No signal appears at theoutput of the receiver which is incorporated into a radiotelemetricsystem (not illustrated in the drawing).

The dropped-down resistance of the G-M counter 1 resulting from adischarge occurring therein disturbs the phase and amplitude balance inthe inverter feedback circuit which results in a momentary dropping ofthe amplitude of the inverter oscillations to nearly zero. This, inturn, causes forth an abrupt voltage fall across the G-M counter 1 andcauses the extinction of the discharge therein, whereupon the inverterrestores its normal operating conditions until a next ionizing particleis registered.

The short-time diminishing of the amplitude of the inverter oscillationsand, consequently, of the amplitude of the r.f. waves emitted by theinverter, correspondingly causes a pulse to appear at the output of thereceiver of the radiotelemetric system.

Thus, the amplitude modulation of the r.f. signals occurs due to the GMcounter 1 being interconnected with the inverter positive feedbackcircuit through the piezo-electric transformer 9.

As it is evident from the above description of the radiocapsuleoperation some of the elements thereof (transformer 9, inductance 7, G-Mcounter I) perform a number of functions at a time. It is due to thisfact that a high efficiency factor (mounting to 0.95) of the inverter ofthe present radiocapsule, high output power of the r.f. signals andjamming invulnerability of the radio transmission are attained.Provision of monofrequent amplitude-modulated r.f. signals ensures therequired time resolution of the registration of ionizing radiation andmakes simpler the construction of the radiotelemetric system as a whole.

The time for the continuous operation of the hereinproposcd radiocapsulewithout requiring replacing of its power source is at least 48 hours.This makes the radiocapsule applicable in effecting prolongedmeasurements of ionizing radiation in the cavities of human body,particularly, in the gastro-intestinal tract. Furthermore, the presentradiocapsule will find application for locating intestinal hemorrhagesand tumors through the use of radioactive isotopes, as well as ininvestigating the cycles of accumulation of radioactivity in the uterinecavity.

What is claimed is:

1. A radiocapsule for registering ionizing radiation in I the cavitiesof a human body, comprising a detector means adapted to registerionizing particles in said cavities of the human body; an r.f.oscillator means simultaneously producing a voltage for supplying tosaid detector and radio signals modulated by said detector at the momentwhen each of the ionizing particles is being registered, said r.f.oscillator means including an r.f. emitting means and further comprisingan inverter for a dc. voltage into an ac. sine voltage, said inverterhaving an input electrically connected with said detector and an outputgenerating modulated radio signals; said inverter including a transistorhaving an input providing the modulating input of said inverter; apiezoelectric transformer means connected to said r.f. oscillator, saidpiezo-electric transformer means having an input connected to the outputof said transistor and said output being electrically connected with theinput of said transistor and with the detector so as to ensure amplitudemodulation of the radio signals; and a dc. voltage source means.

1. A radiocapsule for registering ionizing radiation in the cavities ofa human body, comprising a detector means adapted to register ionizingparticles in said cavities of the human body; an r.f. oscillator meanssimultaneously producing a voltage for supplying to said detector andradio signals modulated by said detector at the moment when each of theionizing particles is being registered, said r.f. oscillator meansincluding an r.f. emitting means and further comprising an inverter fora d.c. voltage into an a.c. sine voltage, said inverter having an inputelectrically connected with said detector and an output generatingmodulated radio signals; said inverter including a transistor having aninput providing the modulating input of said inverter; a piezoelectrictransformer means connected to said r.f. oscillator, said piezo-electrictransformer means having an input connected to the output of saidtransistor and said output being electrically connected with the inputof said transistor and with the detector so as to ensure amplitudemodulation of the radio signals; and a d.c. voltage source means.